Numpy: calculate based on previous element?

Question

Say that I have array x and y:

x = numpy.array([1,2,3,4,5,6,7,8,9,10])  # actual content is the a result of another calculation step
         


        

Answer 1

This is how to do it with numpy:

import numpy as np
x = np.array([ 1, 2, 3, 4, 5, 6, 7, 8 ,9, 10 ])
y = np.array([ 50 ])
for i in np.arange(len(x)):
    y = np.append(
                  y,
                  ( y[-1] * 2 + x[i] )
                  )
y = y[1:]

print(y)